Conceiving after m/c. Please help..?

Hello everyone. Just a quick question. Maybe im just thick or stupid buuuut...  When i began to bleed the heavy bright red blood during my miscarriage i classed that as CD1. Ofcourse that has changed my fertility window. I was 6 weeks preganant and i have done another pregnancy test which has said negetive (just to check hormone levels). This week it is saying i am in my fertile window and to pay special attention On Wednesday 18th March. The dr has given me the all clear to start trying again. I just wondered has any one else been in the same scenario?